Refrigerated display cases have long been used by merchants, such as in grocery stores, for refrigerating or freezing the food products in order to safely preserve them against deterioration while at the same time displaying them in an available and visible manner which is attractive to customers. A problem arises, however, because people prefer considerably different environmental temperatures than are appropriate for food preservation and yet, self serve stores prefer display cases which are open to provide easy access to products in order to encourage their purchase. The resulting problem is that air may freely circulate between the store environment and the interior of the display cases.
This free communication has two undesirable effects. It cools the store environment and warms the interior of the display cases. The cooler store is less comfortable for customers and therefore more energy must be used to heat the store. The warmer display case reduces shelf life of the food products. The free communication also facilitates the formation of frost and ice in the display cases. All this requires more energy.
Designers of display cases have sought to reduce these problems by providing for the circulation of cool air along a path within the display case and by making the access opening of freezer cases at their top to take advantage of the heavier weight of cold air. However, with the recent sharp rise in energy costs, the undesirable heat transfer from store environment into refrigerated display cases has been a matter of increased concern for store proprietors.
One attempt to solve this problem is the provision of overnight covers over the display cases. Although these are quite helpful and effective during the night hours, they must be removed during store operating hours so that customers can view and have access to the products. Thus, during the important operating hours when store temperatures are of greater concern, the overnight covers are not used so the same old problems exist.
Another approach has been the provision of sliding or hinged solid doors. Although such doors provide an effective barrier between the store environment and the interior of the display cases, they also require more customer effort to gain access to the displayed products. Thus, they are not only a barrier to air circulation, but are also a barrier to customer access to food products and therefore a deterrent to sales. Additionally, such rigid covers require significant maintenance and often are provided with heating elements on the interior surface which are made necessary in order to remove moisture condensation on the barrier in order to maintain a clear, transparent barrier which does not reduce the visibility of the products. Additionally, such solid barriers are considerably more expensive than embodiments of the present invention and are considerably more difficult to retrofit to existing display cases.
It is therefore an object of the present invention to provide an improved refrigerated display case cover which is inexpensive, provides an effective barrier to air circulation between the store environment and the interior of the display case and yet maintains maximum product visibility and customer access to the products.
A further object of the present invention is to provide a barrier which permits the refrigerated display case to be maintained at a colder and more constant, uniform temperature while permitting the store to be maintained at a warmer more comfortable temperature and at the same time to provide an energy cost savings.
It is a further object of the invention to provide a barrier which substantially reduces the heat transfer from the store environment into the display case so that food may be kept fresher and will have a longer shelf life.
Yet another object of the invention is to provide a barrier which does not sufficiently attract moisture condensation and which reduces the frost and ice buildup within the display case therefore requiring fewer defrost cycles and less labor because it needs to be cleaned less often.
Yet another object of the present invention is to provide a display case cover with the above advantages but which can also be conveniently removed from the display case access opening to provide easy access for restocking and cleaning of the display cases.
Yet another object of the present invention is to provide a display case cover which is easily attached to existing cases.